The purpose of the Mid-America Adolescent Sexually Transmitted Diseases Cooperative Research Center (MASTD CRC) is to conduct integrated, multidisciplinary research on important issues related to sexually transmitted infections in adolescents. The goal is to examine longitudinally the behavioral, psychosocial and biological risk and protective factors related to sexually transmitted infections of the lower genital tract among middle adolescent women. The five projects will be supported by an Administrative Core (A), a Clinical Core (B) data, a Laboratory Core (C) and Biostatistical Core (D). A behavioral epidemiology project will investigate the psychosocial (sociocultural and family, social/sexual networks, attitudes), partner-specific interpersonal relationship (relationship quality, communication), and coitus-specific (sexual interest, substance use) factors associated with risk and protection. Two projects will focus on organisms causing genital ulcer disease, cervicitis and PID. One will elucidate the nature of the interaction between the gonococcus and the cervical cell surface. The other will examine the relationships of omp1 genotype, immune factors and repeated lower genital tract chlamydia infections in adolescent women. The fourth project will explore the pathogenesis of human papillomavirus infections with emphasis on the controlling susceptibility to infection. The fifth project investigates important aspects of vaginal immunity as influenced by reproductive hormones and sexually transmitted pathogens (C. trachomatis, N. gonorrhoeae, T. vaginalis). The multi-disciplinary research conducted by this consortium agreement between Indian University and NorthWestern University, Louisiana State University and University of Iowa Schools of Medicine will increase out understanding of the complex interplay of actors that increase risk for and protected from STI. Real time video tele-conferencing will be used to facilitate collaboration, interchange of ideas and cross-disciplinary research across campuses. The findings from the studies conducted by the center investigators will facilitate intervention-oriented research for primary and secondary prevention of STD for adolescents.